I agree on capping (or recapping in my case) horde towers. They are a complete pita to get all the way in. I find I can get up okay, but can't get into the top room where the flag is with any expedience. End up with 1, maybe 2, toons in the room with the rest jogging in place outside watching my solo/duo die.

Alliance bunkers are much better. I drop an earthbind totem at the base of the last set of stairs and position my team at the flag. I can hit alliance that come in and then murder them as they move slowly up the last set of stairs.

As previously stated, winning is a good exp rate and losing is a crappy exp rate. Still, its fun.

Now, AV weekend? Spend all weekend in there. Good exp regardless and if you win more than you lose, you'll fly through levels.